PSLE Cathy had a box of gold beads and brown beads in the ratio 17 : 8. She removed an equal number of gold beads and brown beads from the box. The ratio of the number of gold beads and brown beads left in the box became 5 : 2. What percentage of the beads were left in the box?
|
Gold beads |
Brown beads |
Difference |
Total |
Before |
17x1 = 17 u |
8x1 = 8 u |
9x1 = 9 u |
25x1 = 25 u |
Change |
- 2 u |
- 2 u |
|
|
After |
5x3 = 15 u |
2x3 = 6 u |
3x3 = 9 u |
7x3 = 21 u |
When Cathy removed an equal number of gold beads and brown beads, the difference between the number of gold beads and brown beads at first and in the end remains the same.
LCM of 9 and 3 is 9.
Percentage of the beads left in the box
=
2125 x 100%
= 2125 x 100%
= 84%
Answer: 84%